7th June 2025

Palmoplantar keratoderma (PPK)

Keratoderma: marked thickening in the epidermal skin layer.

Palmoplantar: refers to the skin on the palms and sole which are most affected by the disease

Hereditary PPK is caused by a mutation in the genes that either code a protein in the keratin
Can manifest as a sole dermatological disease, i.e. non syndromic or along with extra cutaneous manifestations, i.e. syndromic-i.e. in relation to an inflammatory skin condition (e.g. eczema or psoriasis), systemic inflammatory disease, internal cancers etc.
Inheritance:
- Autosomal dominant, recessive or X linked.
- Mitochondrial inheritance has also been reported.

Careful history regarding onset of symptoms (e.g. infancy or childhood), a positive family history of parents’ consanguinity may support the diagnosis
Examination should include the entire skin surface, nails, hair and mucous membranes. E.g. diffuse/focal/punctate/striate
- Distribution:
  - Presence or absence of extension to the dorsal area of palms and soles, around the digits
- Morphology:
  - Presence of hyperkeratosis which presents as waxy and compact areas with fissures associated with erythema and desquamation
- Extracutaneous findings (e.g. ocular keratitis, hearing loss, cardiac abnormalities and internal malignancies)
Histopathology:
- Mainly shows hyperkeratosis and acanthosis. The presence of epidermolysis is important to note as it differentiates epidermolytic-PPK from non-epidermolytic-PPK Image Source: Wikimedia Commons (2017). Palmoplanta Keratoderma, Licensed under a creative commons licence. Available for free at: https://en.wikipedia.org/wiki/Palmoplantar_keratoderma (Accessed 22 May 2025).